This specification relates generally to search engines.
The World Wide Web (the “web”) contains a vast amount of information. A user can use a search engine to find the information on the web in which the user is interested. For example, a user can use the search engine to find news articles. The search engine retrieves news articles from web sites and presents them to the user as search results, which generally each include some text describing the corresponding news article and a link to the article itself. The search engine can group multiple articles that are reporting on the same news story together and present the multiple articles as a group. When deciding the order of presentation for new articles and groups of news articles, the search engine can consider several factors, such as the date of publication, the quality of the source, and so on.